Fig. 9
From: Evaluation of candidate geomagnetic field models for IGRF-12
Left plot shows differences \({~}_{i,j}{g_{n}^{m}}\) as defined in Eq. 2 between SV-2015-2020 candidate models and their arithmetic mean model M as a function of the index of the spherical harmonic coefficient (running from \({g_{1}^{0}},{g_{1}^{1}},{h_{1}^{1}},{g_{2}^{0}},{h_{1}^{1}}\) etc indexed 1,2,3,4,5, etc). The vertical line locates the zonal coefficient (m=0) for each SH degree n. Right plot shows the SH degree correlation i,M ρ n (Eq. 11) of SV-2015-2020 candidate models with the arithmetic mean model M